This invention relates to a method and apparatus which incorporates air modifying agents, particularly, though not solely, air freshening, fragrancing and/or deodorising substances, or insecticides.
It is well known to provide sources of air freshening, fragrancing and/or deodorising substances and insecticides in a vaporisable form such that, upon vaporisation of appropriate substance, an active vapor is dispersed into the surrounding air.
Often it is desirable to use an electrically powered fan or heater to aid vaporisation and/or dispersion and to this end a small battery driven power source is typically provided. However batteries often lead to inconvenience in that they constitute a further component and, in use, run down or decay and have to be replaced.
The present invention seeks to address at least some of the shortcomings occasioned by the use of batteries whilst, at the same time, providing a novel, active means of determining the presence of, and preferably dispersing, an air modifying agent.
Accordingly, in one aspect, the invention provides a method for dispersing an air modifying agent in air, the method comprising the steps of entraining the air modifying agent in air modifying agent reservoir means to provide a source of the air modifying agent; entraining an electrolyte in electrolyte reservoir means to provide a source of an electrolyte; providing a plurality of electrode means arranged to be in electrical contact with each other via the electrolyte such that in use the arrangement generates an electrical potential; providing an electrical dispersion device operable by the electrical potential to effect or assist dispersion of the air modifying agent from an outlet of the air modifying agent reservoir means into an air space; and disposing the said reservoir means such that the outlet of the air modifying agent reservoir means is in relative proximity to the electrical dispersion device for said dispersion of the air modifying agent into the air space; wherein the electrolyte reservoir means and the electrode means are not present solely as a discrete sealed battery unit removably electrically connected to the electrical dispersion device. The above steps are performable in a variety of orders, as will be understood by one of skill in this art; they are not limited to the order recited above.
According to a second aspect, the invention provides apparatus for dispersing an air modifying agent in air, the apparatus comprising: a housing partially enclosing an air space; electrolyte reservoir means disposed within the housing and providing a source of an electrolyte; a plurality of electrode means disposed within the housing and arranged to be in electrical contact with each other via the electrolyte such that in use the arrangement generates an electrical potential; air modifying agent reservoir means disposed within the housing and providing a source of the air modifying agent; and an electrical dispersion device operable by the electrical potential to effect or assist dispersion of the air modifying agent from an outlet of the air modifying agent reservoir means into the air space and thence into surrounding ambient air; wherein the outlet of the air modifying agent reservoir means is disposed in relative proximity to the electrical dispersion device for said dispersion of the air modifying agent into the air space and the electrolyte reservoir means and the electrode means are not present solely as a discrete sealed battery unit removably electrically connected to the electrical dispersion device.
The air space partially enclosed by the housing is in air flow communication with the surrounding ambient air, e.g. via one or more apertures in the housing. In this way, dispersal of the air modifying agent into the air space leads to dispersal of the agent into the surrounding air.
The electrolyte reservoir means is suitably a dimensionally stable solid or semisolid substance or structure capable of retaining within its volume a solvent such as water, containing an electrolyte (e.g. a salt) dissolved therein. The arrangement permits the dissolved electrolyte to contact the electrode means for establishing the electrical contact. Alternatively, but less preferably, the electrolyte reservoir means may be a volume of a liquid carrier, e.g. water. The air modifying agent reservoir means may also be a volume of a liquid carrier, e.g. water, but is more suitably a dimensionally stable solid or semisolid substance or structure capable of retaining within its volume an air modifying agent, while permitting the air modifying agent to exit from an outlet, to disperse the air modifying agent into the air space and thence into the surrounding air. The outlet typically comprises a surface of the reservoir which is in contact with the air space (suitably over a large surface area), from which the air modifying agent disperses in vapor or mist form into the air space and to which further air modifying agent is drawn from the interior of the reservoir means.
Examples of such reservoir means include gels (for example natural or synthetic polysaccharide gels), absorbent mats, felts or pads, wicks, bulk liquid water or any combination thereof. The reservoir means (other than bulk liquid water) may be permanently solvated (e.g. hydrated) or may be stored in a relatively unsolvated (e.g. dehydrated) form and solvated when required for use.
The reservoir means typically occupy a major portion of the base of the housing, and are suitably disposed in the housing in such a way as to leave substantially no intervening space between each other. More particularly, the electrolyte reservoir means may underlie and/or be in contact with the air modifying agent reservoir means to support the same. Where the reservoir means are identical, or are composed of substances (e.g. gels) which are miscible to form a unitary form or structure, the two reservoir means may preferably be combined into a generally unitary form or structure, provided always that the form or structure permits dispersion of the air modifying agent from it in relative proximity to the electrical dispersion device. The phrase xe2x80x9cin relative proximityxe2x80x9d herein refers generally to proximity of the outlet of the air modifying agent reservoir means to the electrical dispersion device, relative to the major part of the volume of the electrolyte reservoir means (or, when the two reservoir means are combined into a generally unitary form or structure, the major part of the volume of the unitary reservoir means).
The air modifying agent can be selected, for example, from air freshening substances, air fragrancing substances, air deodorising substances, anti-bacterial agents and insecticides. For air freshening applications, the air modifying agent will typically comprise a gelled, fragrant substance formed by combining water, gelling agent and a fragrance. The gelling agent and water comprise the air modifying agent reservoir means. Surprisingly, we have found that when using carrageenan as a gelling agent, even in concentrations of 2.5% by weight, sufficient electrolytic activity is generated, using a variety of electrodes, to power a small electric motor with fan. Such a gelling agent and water can therefore also comprise the electrolyte reservoir means, and this leads to the option, mentioned above, that the two reservoir means can be combined into a generally unitary gelled form. It is known that carrageenan is derived from seaweed and it is believed that the salts which occur naturally in seaweed (which include potassium chloride) impart the electrolytic properties to the gelling agent.
Suitable forms of carrageenan include DANAGEL DKL sourced from FMC Litex Limited. This comprises a carrageenan base with calcium acetate and locust bean gum as additives. Other carrageenan based gelling agents could be substituted including FMC Litex products coded VG11S, AF2 and AF10.
Other gelling agents, not so rich in natural salts, may also be used but will require the addition of electrolytes such as, for example, KCl, NaCl and CuSO4. These electrolytes would be mixed with the gelling agent, a bulking agent (water) and the fragrance, the various constituents being selected to ensure a block of vaporisable, fragrant substance is achieved which has sufficient electrolytic activity to, in combination with the chosen electrodes, power the electrical dispersion device chosen to effect or at least stimulate vaporisation.
The air modifying agent need not initially be in the form of a gel. Commonly such agents are also derived from liquidsxe2x80x94either in bulk form or impregnated in mats. If a liquid source of air modifying agent is to be incorporated in apparatus according to the invention then such liquid will be selected for its electrolytic properties or may have electrolytic properties imparted thereto by the addition of suitable electrolytes. In the case of pads, the electrolyte, and even the air modifying agent, may be provided in dry form and activated by the addition of water or other solvent.
The electrode means are in contact with at least the electrolyte reservoir means, and optionally also with the air modifying agent reservoir means. This latter option can enable a particularly compact arrangement of parts within a housing.
The electrode means may take any conventional form and be constructed from any conventional electrode material suitable for an electrolyte cell. The electrode means may, for example, comprise a pair of rod members, having the desired electrical characteristics. The rod members are preferably immersed into the electrolyte. Alternatively, one of the electrodes may for example be formed by the inner surface of the housing, to enable as large an electrode surface area as possible. One or more of the electrodes may, as a further alternative, be provided in granule or particulate form, to maximise the surface area in contact with the electrolyte.
When in granulated form, a conducting carrier is advantageously provided to ensure charges from the individual granules are relayed to a common terminal. By way of example, carbon granules could be held in contact with aluminium foil using a mesh, the mesh allowing the electrolyte to flow about the granules without physically displacing the same.
As will be readily understood, it is necessary for the electrode means to have distinct and different electronegativities in order to generate the electrical potential in the manner of an electrochemical cell. The materials from which the electrodes are constructed may, for example, be selected from zinc, carbon, copper or aluminium. The electrodes may comprise an inert substrate on which an active electrode surface material is provided. The electrolyte reservoir means typically includes conventional antidepolarisation and/or antiplating agents which inhibit depolarisation of the electrochemical cell and/or plating of the electrode means, at least for a time sufficient to enable the bulk of the air modifying agent to be dispersed.
The electrolyte is suitably a water-soluble salt such as a salt of a hydrophobic cation (e.g. a potassium, sodium, ammonium or copper salt). Typical salts include potassium chloride, sodium chloride and copper sulphate. In certain naturally occurring gels, such as carrageenan, salts such as potassium chloride occur naturally; such gels are therefore preferred for use as electrolyte reservoir materials in the present invention. If electrolyte reservoir materials are used which do not inherently contain suitable electrolytes in sufficient amounts, the electrolyte must be added.
The electrical dispersion device is advantageously a fan or other device for causing a flow of air across the outlet (e.g. surface) of the air modifying agent reservoir means. The fan is driven by a small electrical motor powered by the electrical potential generated by the electrochemical cell. Alternatively or additionally, the electrical dispersion device may be a heating device, which assists in vaporisation of the air modifying agent.
The invention enables an electrochemical cell to power the dispersion of an air modifying agent from a reservoir of the said agent, in a more compact, convenient and efficient manner than known hitherto. As mentioned above, it is particularly desirable that the electrode means are in contact not only with the electrolyte but with the source of air modifying agent, as this enables a particularly compact and efficient structure, especially when the air modifying agent reservoir means can itself contain an electrolyte in addition to the electrolyte present in the electrolyte reservoir means.
The arrangement may suitably be such that the electrical dispersion device, the electrolyte reservoir means and the air modifying agent reservoir means are selected so that on operation of the electrical dispersion device the extent of exhaustion of the air modifying agent from the air modifying agent reservoir means corresponds generally to the extent of exhaustion of electrode activity, whereby the operability of the electrical dispersion device indicates the presence of air modifying agent in the air modifying agent reservoir means. An electrical lighting device may, additionally or alternatively, be connected to be powered by the electrical potential generated by the electrode means, to provide a visual indication of the present of air modifying agent.
Moreover, the lighting device may provide an attractive and useful function, in illuminating the apparatus. This illumination may conveniently take place from the interior of the apparatus, which in this case will have at least part of its housing made from a translucent material. Most conveniently, the air modifying agent reservoir means and/or the electrolyte reservoir means may be translucent and the electrical lighting device, which may of course also provide a dispersing effect through any heat it may produce, is immersed therein to illuminate the reservoir means from within.
In general, a variety of electrical devices can be readily envisaged, which can indicate the presence of air modifying agents in a source thereof.
Thus, in a third aspect, therefore, the invention provides a method of indicating the presence of an air modifying agent, said method comprising:
placing electrode means in contact with a source of air modifying agent and in contact with an electrolyte in a manner such that the combination of said electrode means and said electrolyte generates an electrical potential; and
providing an electrical consumer operable by said electrical potential to indicate the presence of said air modifying agent.
The consumer is preferably selected to not only indicate the presence of the air modifying agent but also to effect or assist dispersion thereof.
Preferably said method further comprises mixing said air modifying agent with said electrolyte.
Alternatively said method comprises retaining said electrolyte and said air modifying agent separately, but in juxtaposition.
In a still further aspect the invention provides apparatus for indicating the presence of an air modifying agent, said apparatus comprising:
an air modifying agent;
an electrolyte;
electrode means contactable or in contact with said air modifying agent and said electrolyte to, in use, generate an electrical potential; and
an electrical consumer operable by said electrical potential to, in use, indicate the presence of said air modifying agent.
The consumer may simply be a static device such as a light emitting diode (LED) connected to suitable electrodes and immersed into the electrolyte. However, the consumer preferably has a further function, namely to effect or assist dispersion of the air modifying agent and, to this end, preferably comprises an electrically powered fan or the like.
The air modifying agent is preferably mixed with said electrolyte but, alternatively, may be retained separately but in juxtaposition. In the case of gel-based or modifying agents the gelling agent may be selected having regard to its electrolytic properties. Gelling agents displaying electrolytic properties include carrageenan.
The electrode means may comprise a pair of rod members, having the desired electrical characteristics, which, in use, are immersed into the electrolyte. Electrodes found suitable for use with carrageenan include carbon and zinc electrodes. By way of one alternative, one of the electrodes may be formed by the inner surface of a housing containing the electrolyte and air modifying agent in undispersed form.